Fuel injection for internal combustion engines



April 22, 1958 J. E. WITZ KY 2,831,468

FUEL INJECTION FOR INTERNAL COMBUSTION ENGINES Filed Aug. 4, 1954INVENTOR. JULIUS wnzny United States PatcntO FUEL INJECTION FOR INTERNALCOMBUSTION ENGINES Julius E. Witzlry, Royal Oak, Mich.

Application August 4, 1954, Serial No. 447,874

11 Claims. (Cl. 12332) tion of all air in the pro-combustion chamber theaccom- I panying pressure rise causes a high velocity gas flow in theopposite direction past the fuel inlet resulting in carrying additionalfuel finely atomized into the toroidal main combustion chamber where theremainder of the air is used to complete the combustion.

Another object of the invention is to provide a fuel injection systemfor an internal combustion engine wherein a fuel nozzle in the head of acylinder is received in the throat of a pre-combustion chamber in thehead of a piston reciprocal in the cylinder and wherein the relationshipof the pre-combustion chamber and particularly the throat thereof to thenozzle is such as to initially create a velocity sweeping past theoutletof the nozzle into the pre-combustion where ignition takes placeaccompanied by a rise in pressure resulting in a high velocity gas fiowin an opposite direction past the inlets into the main combustionchamber.

A feature of the invention is a removable member in the head of acylinder supporting a nozzle protruding into the cylinder and receivedin the throat of a precombustion chamber arranged in the head of apiston movable in the cylinder.

Another feature of the invention is the particular contour of the nozzleand the throat of the pre-combustion chamber and their relationship toone another.

2,833,4h8 Patented Apr. 22, 1958 the flow of gases through the passage20. The valve 22 is of a conventional type having a head 24 normallyresting on a seat 26. The head 12 also has an opening 28 therethroughcommunicating with the concavity 18 slightly off center of theconcavity. This opening is characterized in that one end adjacent theconcavity 18 has its wall beveled as at 30. Its other end is internallythreaded as at 32 and intermediate the beveled and threaded wallportions the diameter of the opening is enlarged to provide an annularpassage 34. The purpose of this passage is to receive and support aninjector per se indicated generally at 36 and to be hereinafterdescribed.

A piston 38 reciprocal in the cylinder has a head 40 and a skirt 42'carrying conventional piston rings 44. Thehead has a convexed facecomplementary to the concavity in the cylinder head and a concentricallydisposed annular concavity 46 providing in combinationwith the concavityl8 and the wall of the cylinder a main combustion chamber 48, andarranged within the head of the piston slightly off center is apro-combustion chamber, 50 having a throat 52 opening centrally, of theannular concavity 48. I

The pre-combustion chamber is preferably globular in general contour andhas on its innerwall a raised conoidal surface 54 oppositely disposedwith relation'to the throat, and the throat 52 is characterized in thatit has a greater diameter at its entrance to the pre-combustion chamberthan at its entrance to'the main combustion chamber and that itsentrance to the main chamber is flared to blend with the inner rim ofthe annular concavity 48 to provide in combination therewith aconstrictedlip 56, the purpose of which will hereinafter appear.

The fuel injector 36 includes a plug 58 having a tapered end ascomplementary to the beveled or tapered portion 3d of the wall oftheopening 28. The other end 62 of the plug is reduced in diameter toprovide a shoulder 64 having a slot 66, for the reception of a hollowpin 68 threaded in thewall of the opening. The pin 68 serves to locatethe plug 58 in the opening 28 so that the tapered end of the plug seatssnugly in the beveled portion of the opening, and a retaining nut 70received by the threads Yet another feature of the invention is theutilization of a low pressure fuel injection wherein air under highvelocity seizes the fluid as distinguished from the conventional wherefuel under high pressure is injected into the air.

With these and other objects and features in view which may be incidentto the improvements, the invention consists in the parts andcombinations thereof to be hereinafter set forth and claimed with theunderstanding that the several necessary elements comprising myinvention, may be varied in construction, proportions andarrangement,-without departing from the spirit and scope of the appendedclaims.

The single figure is a vertical sectional view of a cylinder for aninternal combustion engine partly broken away and a head thereforillustrating the invention as applied.

Referring to the drawings for more specific details of the invention,Ill designates a cylinder of an internal combustion engine, and 12indicates the head thereof. As shown, the cylinder is water jacketed asin'dica'tedat 14 and has an inner lining 16. The head has a concavity 18facing the interior of the cylinder, and an exhaust passage 2t) andintake not shown opening through the concavity preferably adjacent thecircumference thereof, and

a valve 22 mounted for reciprocation in the head controls 32 in theouter end of the opening bears against the shoulder 64 and serves towedge the plug against the beveled portion of the opening with sealingeffect.

A chamber 72 in the tapered end of the plug communicates with aconcentrically disposed bore 74, which, in turn, communicates by way ofa duct 76 with the annular passage 34. The chamber also hascommunication by way of a duct 78 with a passage 80 extended axiallythrough the plug and .adapted to be connected to a low pressure pump,not shown;

A nozzle 82 threaded in the chamber '72 protrudes into the maincombustion chamber and is received in the throat 52 of thepro-combustion chamber. The nozzle is characterized in that it is bulbarin general contour having an enlarged diameter adjacent its free end anda decreased diameter at its neck root. The free end is conoidal, asshown at 84, and the body is contoured to correspond to the contour ofthe throat with substantial clearance. The nozzle has a valve chamber analigned with the bore 74 in the plug 62 and equi-spaced radial ports 88preferably flared and opening at the enlarged diameter of the nozzle. Aneedle valve 90 slidable in the valve chamber is urged by a spring 92seated in the bore 74 to close the ports and a duct 94 connects thevalve chamber 86 to an annular passage 96 which in turn communicateswith the passage 78 leading to the axial passage 80.

In a normal operation upon combustion on the exhaust stroke, the mainand pre-combustion chambers are emptied. On the intake stroke thecylinder is ew combustion air.

On the compression stroke as the piston 40 approaches the nozzle 82 thelips 56 on the head of the piston receives the bulbous-tip of the nozzlewith small clearance resultin in a vigorous movement of air sweepinginto the pro-combustion chamber 5%). This high velocity movement of theair past the fuel orifices carries fuel into the pre-combustion chamber.if a low pressure injection pump is used at the moment when the pistonreaches the buibar tip or" the nozzle during the compression stroke, alow pressure injection starts and such pressure is adequate because thefuel does not of necessity penetrate the combustion air to anyappreciable amount. No atomization is required since the high velocityof the air passing the orifices 83 assures excellent distribution andatomization of the fuel and furthermore the high velocity of the airlowers the pressure forward of the orifices. In other words, contrary tothe conventional, the air is seeking the fuel rather than the fuelseeking the air. i

The burning of the fuel starts with a very short ignition lag becausethe air used for atomization has a temperature already higher than theignition temperature of the fuel, and the following fluid is burned innascent as the fast moving air ignites, cracks and burns the fuel asfast as it leaves the nozzle.

After the piston passes top dead center and all the air in thepro-combustion chamber is utilized for combustion, the accompanyingpressure rise results in a high velocity gas flow in the oppositedirection past the fuel orifices carrying fuel finely atomized into thetoroidal main chamber utilizing the remainder of the air to com pletethe combustion,

By using a low pressure injection pump'the termination of injection isdetermined by the piston movement to be effective atthe moment the lipsof the piston uncovers the bulbar tip of the nozzle in the power stroke,the injection must be completed. The maximum duration of injection isdetermined by the time the piston covers the tip of the nozzle.

Although this invention has been described in connection with certainspecific embodiments, the principles involved are susceptible ofnumerous other applications that will readily occur to person skilled inthe art. The invention is therefore to be limited only as indicated bythe scope of the appended claims.

Having thus described the invention what I claim as newand desire tosecure by Letters Patent is:

1. In an internal combustion engine, a cylinder, at head therefor, aremovable plug in the head, a fuel nozzle supported on theplug andprotruding into the cylinder having an outwardly flared body andradially disposed ports, a piston reciprocable in the cylinder, atpro-combustion chamber in the piston having a throat commensurate to andreceiving the nozzle and a spring pressed valve for control of the fuelflow.

2. In an internal combustion engine. a cylinder, 3, head therefor havinga cavity facing the chamber of the cylinder, a piston reciprocal in thecylinder, an annular cavity in the top of the pistonoppositelydisposedwith relation to the cavity in the head and providingin conjunction therewith a toroidal main combustion chamber, apre-combustion chamber in the piston having an inwardly flared throatopening concentrically of the annular cavity, a removable plug in thehead of the cylinder, a fuel nozzle having an outwardly flared body andoutwardly flared ports on the plug and extending into the maincombustion chamber and received by the throat, and a spring pressedvalve in the nozzle for control of the ports. I

3. In an internal combustion engine, a cylinder, a head thereon and apiston movable inthe' cylinder, a toroidal cavity in the top of thepiston providing in conjunction with the heada main combustion chamber,a

filled with pro-combustion chamber in the head of the piston having aninwardly flared throat opening concentrically of the toroidal cavity, aremovable plug in the head of the cylinder, 21 fuel nozzle supportedby'the plug and received by the throat having an outwardly flared bodyand outwardly ports and a spring pressed valve in the nozzle for controlof the ports.

4. In an internal combustion engine, a cylinder, :1 head thereon and apiston movable in the cylinder, a toroidal cavity in the top of thepiston providing in conjunction with the head a main combustion chamber,a pro-combustion chamber in the head of the piston having a throatproviding communication between the combustion chambers andcharacterized in that it is contracted at its entrance to the maincombustion chamber and flared inwardly, a plug compression sealed in thehead of the cylinder, a fuel nozzle supported thereby having anoutwardly flared body and radially disposed outwardly flared orificesand a spring pressed valve in the nozzle for control of the orifices.

5. In an internal combustion engine, a cylinder, a head for the cylinderhaving a cavity facing the interior of the cylinder and a piston movablein the cylinder, a toroidal cavity in the top of the piston providing inconjunction with the cavity in the head, a main combustion chamber," apre combustion chamber in the head of the piston having a threatproviding communication between the chambers characterized in that thediameter to the throat is greater at its entrance of the precombustionchamber than at its entrance to the main combustion chamber, a plugcompression sealed in the head having a chamber therein and a fuel inletcommunicating with the chamber, a nozzlefitted in the chamber in theplug having a greater diameter adjacent its tip than at its neck andradially disposed orifices flared outwardly at the greater diameter anda spring pressed valve in the nozzle for control of the orifices.

6. In an internal combustion engine having a cylinder, 2. head thereforand a piston reciprocal in the cylinder, a' toroidal cavity in the headof the piston providing in conjunction with the head a main combustionchamber, a precombustion chamber in the piston, a throat providingcommunication between the combustion chambers characterized in that thewall defining the throat is flared inwardly and provides in conjunctionwith the wall defining the toroidal cavity in the piston a pronouncedlip at the entrance of the throat, a fluid nozzle supported by the headand received by the throat characterized in that it has a greaterdiameter adjacent its tip than of its neck and that the clearancebetween the nozzle and throat is variable, radially disposed outwardlyflared orifices in the nozzle arranged substantially at thegreater'diameter of the nozzle, and aspring pressed valvein the nozzlefor control of the orifices.

7. An internal combustion engine comprising a cylin- (161', a headthereon having a concaved surface facing the interior of the cylinderand a piston reciprocal in the cylinder having an annular cavityopposite the concaved surface of the head, a main combustion chamberbetween the head and the piston, a precombustion chamher in the piston,having an inwardly flared throat providing communication betweenthe'chambers, an annular lip at the entrance of the throat, a fuelnozzle supported on the head and received by the threat, the nozzlehaving a. greater diameter adjacent its free end than at its neck,radially disposed outwardly flared orifices in the nozzle, and a springpressed valve in the nozzle for control of the orifices.

8. An internal combustion engine comprising a cylinder,-.a head on thecylinder and a piston reciprocable in the cylinder, a main combustionchamber, a pro-combustion chamber in the piston, a throat providingcommunication between the chambers, the wall defining the throat beingflared inwardly of the pro-combustion chamber and a fuel nozzlesupported by the head and received by the throat, the wall of the nozzlebeing flared outwardly from the neck thereof so that the clearancebetween the throat and nozzle may be variable during both thecompression and retractile stroke of the piston, and a valve in thenozzle for control of fluid flow through the nozzle.

9. A fuel injector including a body having a fuel supply passagetherein, a conical head on one end of the body, a shoulder on the otherend of the body for reception of a compression member, a chamber in theconical head, a fluid nozzle supported in the chamber, an axial bore inthe nozzle, radially disposed outwardly flared orifices communicatingwith the axial bore, a spring pressed plunger in the bore, a passageconnecting the bore to the fuel supply passage through the body meansfor venting the bore and a needle carried by the plunger for control ofthe orifices.

10. An internal combustion engine comprising a cylinder, a head on thecylinder and a piston reciprocal in the cylinder, a main combustionchamber, -a pre-combustion chamber in the piston, a throat connectingthe chambers characterized in that it has a small diameter at itsopening into the main combustion chamber and a relatively large diameterat its opening into the precombustion chamber, a fuel nozzle supportedon the head and received by the throat having a small diameter at itsroot and a relatively large diameter adjacent its free end, the relationof the throat to the nozzle being such as to provide a variableclearance whereby a high constant velocity of fuel impregnated air andgas is attained in both directions of movement of the piston.

11. In an internal combustion engine a cylinder, a head therefor, apiston reciprocal in the cylinder, a main combustion chamber, apre-combustion chamber in the head of the piston having a throatproviding communication between the chambers and characterized in thatit has an annular lip at its opening into the main combustion chamber ofsmaller diameter than the diameter of its opening into thepre-combustion chamber, a fuel nozzle supported on the head and receivedby the throat having an outwardly flared body commensurate with thethroat and a tip having outwardly flared ports therein and a valve inthe nozzle for control of fluid flow through the nozzle.

References Cited in the file of this patent UNITED STATES PATENTS1,633,541 Braren June 21, 1927 2,488,857 Firing Nov. 22, 1949 2,505,999Smith May 2, 1950 2,619,078 Witzky et al. Nov. 25, 1952 2,692,586 Kaniutet al. Oct. 26, 1954 FOREIGN PATENTS 485,862. Germany Nov. 9, 1929489,782 Germany Jan. 22, 1930 175,433 Switzerland Feb. 28, 1935 OTHERREFERENCES Ser. No. 251,007, Wiebicke (A. P. C.), published May 11,1943.

